Efficient formalism for large scale ab initio molecular dynamics based on time-dependent density functional theory

TL;DR

This paper introduces a novel 'on the fly' AIMD method inspired by Ehrenfest dynamics, which efficiently evolves electronic orbitals without explicit orthogonality constraints, enabling large-scale simulations.

Contribution

The paper presents a new AIMD approach that speeds up calculations and automatically preserves wave function orthogonality, suitable for large systems.

Findings

Speeds up AIMD simulations compared to standard Ehrenfest dynamics

Automatically preserves wave function orthogonality

Enables large-scale ab initio molecular dynamics

Abstract

A new "on the fly" method to perform Born-Oppenheimer ab initio molecular dynamics (AIMD) is presented. Inspired by Ehrenfest dynamics in time-dependent density functional theory, the electronic orbitals are evolved by a Schroedinger-like equation, where the orbital time derivative is multiplied by a parameter. This parameter controls the time scale of the fictitious electronic motion and speeds up the calculations with respect to standard Ehrenfest dynamics. In contrast to other methods, wave function orthogonality needs not be imposed as it is automatically preserved, which is of paramount relevance for large scale AIMD simulations.